Transition Levels/QNH/QFE!

[Baron buzz]

I have a few questions regarding the above.

1) What is the transition level in Canada? Is it the same as the US, ie: FL180?? Or anywhere else in the world for that matter.

2) What is the standard operating procedure for both the US and Europe as regards setting QFE? Do airlines actually use it? I am currently under the impression that the only time QFE is set in Europe is by the military and also by PPL's.

3) Since commercial aircraft have two altimetres (per pilot) am i correct in saying that one is set to FL's and the other QNH??

4) Also, just out of interest, does the FAA regulate Canadian Air Transport or does Canada have its own version?

Many thanks in anticipation !

[Capt Claret]

Barron Buzz

In Australia, I've yet to see a commercial aircraft with more than three altimeters.

Each pilot has an altimeter and the third is a standby. They are set (depending on company S.O.P.) to 1013 at our transition altitude (of 10000') during climb, and reset to QNH on descent when approaching out transition level of FL110.

[PPRuNeUser0172]

Can only answer part of your question

In Canada, it is QNH ops up to FL180 where 29.92/1013 is set.

In Europe I think you are right with regards to QFE, the military are certainly QFE ops at airfields. Couldnt comment on PPL type flying.

I am sure many other will have the full answers, hope this helps

DS

[HEATHROW DIRECTOR]

Q.2 I think you are right. At one time the the BEA used to use QFE, as did several of the smaller UK airlines plus Aer Lingus and some east European operators. However, when I retired 2 years ago I think just about everyone except military and tiddlers used QNH. Hopefully someone with current experience will answer too..

[Baron buzz]

Thanks for the above information gents, much appreciated. Your answers were what i thought, but just wasnt sure upon. I do have another quickie if you can...

1) Am i correct in saying the only way a pilot will know how high he is above a certain airport, is by calculating it. Ie: By applying the height of the airfield above/below sea level to the current QNH altitude/FL? Or another way of saying it, since QFE is not set anywhere, on no instrument will the height above an airfield be displayed...?

Thanks again.

[simfly]

It's failrly straight forward. The altimeter if set to QNH will give you your height above sea level, so If you know the height of the airfield below, you simply take the airfield's height away from your altitude. :ok: Unless you call the airfield up and ask for the QFE, that's the only way you do it.

[snbower]

Just for info.

The Ryanair flights into Leeds/Bradford are often given the QFE. This may be when they are performing a visual approach. Can't remember.

Si :)

[PPRuNeUser0172]

Thats probably because Ryanair pilots aree too stupid to subtract airfield elevation from their height ASL................

:E

[keithl]

Don't know if my company is what you called a "tiddler", but we are certainly one who still uses QFE. We may conform in due course, but it's an old debate, it was going before I started flying and continues now I've retired. I took part in the RAF's brief flirtation with QNH and its return to QFE and have come to the conclusion that it doesn't matter much as long as you are clear about the difference!

On another point, when we have one altimeter set to 1013 (29.92) the other one is set to QNH for terrain clearance reasons.

[reynoldsno1]

In Canada, it is QNH ops up to FL180 where 29.92/1013 is set.
Shouldn't that be 18,000ft (i.e. transition altitude) - the next available FL (transition level) above that will depend on the QNH relationship to the SPS?

[PPRuNeUser0172]

Reynoldsno1

You are indeed correct, retiring back to my box as I type, Sir

Yours

DS

Ps that is a very low reynolds no?..............oh I get it, its irony, either that or you are a very odd shape.

[reynoldsno1]

some would say both........;)

[fireflybob]

>It's failrly straight forward. The altimeter if set to QNH will give you your height above sea level, so If you know the height of the airfield below, you simply take the airfield's height away from your altitude. Unless you call the airfield up and ask for the QFE, that's the only way you do it.<

When you are flying on QNH you are at an ALTITUDE (above msl) and when on QFE at a HEIGHT (above aerodrome/touchdown level). Also it's the airfield ELEVATION (ie amsl) rather than "height".

As correct altimetry is so critical to safe flight it is important that the correct phraseology is used and understood.

As has been said above the QFE/QNH arguement has been around since aviation began. There are pros and cons on both sides. However try operating out of places like Nairobi (circa 5,000 ft amsl) or Mexico (circa 8,000 ft amsl) using QFE! You have lots of winding to do to set QFE for approach and/or QNH on Go Around.

Having witnessed many Go Arounds in the back of the Sim I can tell you that when we used QFE there were far more altitude busts compared to when we changed to QNH operation.

[Tinstaafl]

Some other points not specifically addressed:

The regulatory authorities in each country specify their 'take' on transition altitude(s).

Oz uses 10000' (climbing) & FL110 (descending) as the changover point. As QNH reduces below 1013 then flight levels from FL110 progressively become unavailable in order to preserve at least 1000' between aircraft using QNH & a/c using 1013.

USA uses 18,000' as its equivalent to Oz, and then makes FL above that unavailable as QNH reduces below standard. Similar concept but as far as I can see they don't preserve a 1000' buffer to the first availabe FL above 18000' on QNH (or more strictly, '29.92" altimeter' here, since you'll be met with utter confusion here if you start talking about QNHs & hectopascals/millibars).

UK has some entirely random transition altitude that depends on your location & probably the phase of the moon all mixed in with many schools teaching their PPL students to use QFE and the military using using the same. In other words it's not obvious what you should be on where, with whom, and when. Very British in efficiency & ease of use. :hmm:

Other countries have their own idea on how it should be done. Canada may (or may not) use a system that matches the US but they don't have to.

[Shock Stall]

I can't believe any one still uses QFE! Anyone flying A to B needs to know altitude or FL not height. All the charts, approach/departure plates, STARS etc. are printed in feet AMSL, all clearances are given in Feet AMSL (unless you're in China and get it in Meters AMSL!). If you have a problem subtracting aerodrome elevation then how the hell do you fly with QFE? thereby having to do a mental calculation for every clearance, arrival and departure? Even the GA industry who fly around the country in bug-smashers all need to be using the same reference altitude (or MSL) in order to safely communicate altitudes and call over reporting points.

The only advantage to using QFE that I can see is for the inexperiened pilot doing circuit training or similar local flying. It's simple to understand that when the altimeter says 0ft you have either landed or something has gone horribly wrong! Other than that setting QFE and flying towards rising terrain is positively dangerous (if you are relying on 0ft to be ground level) and then there is the problem of "Negative altitude" too.

Heavy jets have a radar altimeter (usually two) which, depending on the aircraft, comes 'alive' at 2500ft AGL. QFE is totally irrelevant, outdated, and in most situations very dangerous.

In response to the Altimeter setting question, ALL altimeters in the aircraft should be set to the same reference (be it QNH, QFE, or ISA), this includes the standby. When things start going wrong, confusion over the reference pressure for individual altimeters is not something you need to be dealing with.

[Meeb]

Oh dear, lots of misinformation coming through on this bonzer thread.... :ooh:

UK has some entirely random transition altitude that depends on your location & probably the phase of the moon all mixed in with many schools teaching their PPL students to use QFE and the military using using the same. In other words it's not obvious what you should be on where, with whom, and when. Very British in efficiency & ease of use

What utter tosh... someone needs to research the climatic & airspace usage system prevelant in the UK!

Shock Stall... do you fly? I hope not with your rather simplistic take on altimetry! You have failed to grasp the concept that QFE is used only for landing , not take off (unless ciruits), and certainly never flight towards 'rising terrain'.

Is it only me, or has PPRuNe been hi-jacked these days with spotters and pratts.... :mad:

[Shock Stall]

Sounds like someone's a bit touchy aye Meeb?. I'm sure I flew with you once.

QFE is dying out (thankfully) either through the retirement of the old dogs who were taught it and can't bare to change, or accidents and incidences making airlines rethink their operations manuals. Yes, used for landing, and what happens if you miss the approach? Great time to be resetting the altimeter. FireflyBob is on the money there. Not necessary with today's machinery, and in most cases very dangerous.

When do you set QFE? At the transition altitude? That can be as high as 18'000ft. or do you wait till you're established on approach? What do you call over the FAF? Altitude or height? (for non-precision). I've never used it and never met anyone under the age of 60 who has, but that's not to say it doesn't have it's advantages.

The rest of the world uses QNH and ISA now, perhaps you should join the party Meeb

And I don't think the site's been hi-jacked by spotters and prats, but there are still the odd arrogant SOBs who know it all, yet can't add anything constructive.

[keithl]

Shockstall I've never used it and never met anyone under the age of 60 who has,

Allow me to introduce myself. I'm 57 and I refer you to my earlier post. I have used both, equally happily, according to various policies at various times and in various countries.

It really is overstating it to say Not necessary with today's machinery, and in most cases very dangerous.

As I said before, it doesn't matter much provided you understand what you're doing.

Finally,the old dogs who were taught it and can't bare to change
You sound a little set in your ways, yourself!

[GlueBall]

4) Also, just out of interest, does the FAA regulate Canadian Air Transport or does Canada have its own version?

FAA = USA. ONLY. :eek: Nothing to do with Canada. ...Just as an Irish policeman wouldn't be regulating traffic in London.

[None]

Both QFE and Metres are used in Ops at Moscow.

[galaxy flyer]

We used QFE at Eastern Airlines and got rid of it a few years before we went under. So did American until the '90s, I believe.

Mike, you are right on the CIS states. I had to (based on Eastern experience) teach some of my C-5 guys going into some CIS states. Amazing, we just sent crews in there with not much more than, "be careful out there." The whole QFE was tough for many to grasp. The GPWS saved at least one of my Westover crews in Manas when they descended to a QFE height with a QNH altimeter setting.
GF

[PPRuNeUser0172]

Whats the big deal with QFE Mr Shock!?

Having done a fair bit of military flying in UK and subsequently other areas where it is QNH ops, there is absolutley no problem with confusion on altimetry settings IMHO, that is of course, providing you are not capacity limited!;)

Just my two'penneth, I feel that the high standard of discipline regarding descent/altimeter checks we receive through training is more than enough for any capable aviator.


DS


PS I totally agree with you Mr Meeb!

[EGPFlyer]

The reason transition levels are different in different countries has to do with ensuring that at the lowest available flight level, there is terrain clearance under all expected conditions of temperature and pressure.

[Tinstaafl]

But christ knows why the UK chooses to have such a god awful system of transition levels. Why do they choose to use variable transition levels? What's wrong with a single transition level? A single level removes any doubt/confusion/uncertainty about what the transition level is, where & when. Surely it's not argued that the UK system is easier to use?

[Giles Wembley-Hogg]

In my humble opinion a common transition altitude of 6000' as suggested in the excerpt by Mike Jenvey is a laudable aim. It would simplify the altimeter setting procedure in the UK without adding the extra complexity of having altitudes in the teens ie "one, one, (eleven) thousand feet" as you hear used in some parts of the world.

I don't really see any benefit to getting rid of QFE for circuits etc. It is a tool available to us which we might as well use.

If there was one improvement I could make to UK altimeter setting procedures it would be for some military units in the South East to provide QNH rather than "regional QNH" (sic) for aircraft in class G. I nearly always have to ask for the QNH after I have transitted thier zone on QFE. (Of course, if I wasn't so lazy, I could work it out myself!)

G W-H

[eggplantwalking]

I totally agree with Shock Stall that QFE is a total waste of time. It might be worthwhile to point out to Buzz Barron that in most airports around the world "transition altitude" is identified on the Jeppesen approach/departure plate(s) and usually given on the airport's ATIS as well, if there is one available. Similarly, this altitude is stated/reviewed in all inflight crew departure or arrival briefing.